Measuring instrument



FIG. 1 is a front view of a measuring instrument showing my design;

FIG. 2 is rear view thereof;

FIG. 3 is a top view thereof; and

FIG. 4 is a bottom view thereof.

The left and right side views of the instrument not shown in the drawings form no part of the claimed design. 

The ornamental design for a measuring instrument, as shown and described. 